The present invention relates to a modular force application device in the form of linear pneumatic drives which may be secured to a coordinate frame structure for a three-dimensional cutting or shaping operation.
U.S. Pat. No. 4,286,490 discloses linear pneumatic drives in which the expansion of a hose extending through at least one, preferably through a plurality of modular bails, is used for applying a force along a line which may be straight or curved in a plane or in space. This type of drive is well suited for three-dimensional shaping or cutting operations. However, due to the fact that the power output takes place in the direction of the main hose expansion, there is room for improvement in the construction of such linear pneumatic drives.
U.S. Pat. No. 3,815,464 discloses a gas operated single stroke servomotor in which the expansion of a hose is employed to drive a knife edge through a restraining belt. Such a single stroke drive is not suitable for repeated cutting operations in a manufacturing process.
U.S. Pat. No. 3,230,812 discloses a punch press which is actuated by an expandable hose extending through two cooperating channels of substantially the same length as the hose. These channels do not form modular units which can be assembled along a common length of hose in any desired number and along any type of curve. These channels are effective only along a straight line. In one embodiment of U.S. Pat. No. 3,230,812 the hose expansion is transmitted to a plurality of punching tools through a like plurality of levers which are journalled to the frame which also supports the channel through which the hose extends. Such a structure is not compact and not adaptable for placing the individual, modular, linear pneumatic drive devices in a coordinate support frame structure.
U.S. Pat. No. 4,277,996 discloses a three-dimensional stamping or cutting apparatus with linear or pneumatic drives in which the cutting force is applied in the direction of expansion of a hose in response to introducing a gas under pressure into the hose. As mentioned above, this type of linear pneumatic drive is quite suitable for the intended purpose, but leaves room for improving the disposition of such linear pneumatic drive devices in a coordinate support frame structure.
It is also known to use piston cylinder drives in three-dimensional trimming machines, for example, for trimming preshaped carpets. The use of expandable hose means in a machine for exerting pressure onto a flat surface is also well known.